don't negotiate until you test ride it. spin the wheels, test the brakes & shifting. look for flaws & mention them. look at wheels while they spin from the top for side to side wobble & from the side for up & down wobble. when you're ready ... take the cash out of your pocket put it on the table & say this: "I'll give you this right now" if the bike is perfect & you get it for your price, terrific. never be afraid to walk - too many bikes out there plus you already have a bike